The subject matter disclosed herein generally relates to fluid flow systems. More specifically, the subject disclosure relates to servo valves in fluid flow systems.
Servo valves are used, for example, in actuation systems where accurate positional control is required. Servo valves may also be used in other fluid flow systems, such as cooling systems or fuel systems. The servo valve utilizes an element, typically a flapper nozzle or a jet pipe to position the servo and regulate flow through the servo valve to control a position of an actuator, valve, or motor to which the servo valve is connected. The position of the flapper nozzle or jet pipe is, in turn, controlled by an electrical signal applied to a torque motor. Servo valves are advantageous because a low power electrical signal is utilized to position the servo and corresponding actuator, valve or motor. Servo valves are, however, complex and costly structures. Further, high pressure gain systems typically require use of the jet pipe type of servo valve over the flapper nozzle type, which is the more complex and costly option of the two. To utilize a flapper nozzle valve in a high gain application requires a decreased gap between the nozzle and flapper requiring closer tolerance manufacturing, and this decreased gap results in high impingement losses of fluid pressure impinging on the flapper as well as increased sensitivity to contamination.